61661401 has 4 divisors (see below), whose sum is σ = 61725492. Its totient is φ = 61597312.

The previous prime is 61661393. The next prime is 61661407. The reversal of 61661401 is 10416616.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 32501401 + 29160000 = 5701^2 + 5400^2 .

It is a cyclic number.

It is not a de Polignac number, because 61661401 - 2³ = 61661393 is a prime.

It is a super-3 number, since 3×61661401³ (a number of 24 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61661407) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30580 + ... + 32533.

It is an arithmetic number, because the mean of its divisors is an integer number (15431373).

Almost surely, 2^61661401 is an apocalyptic number.

It is an amenable number.

61661401 is a deficient number, since it is larger than the sum of its proper divisors (64091).

61661401 is an equidigital number, since it uses as much as digits as its factorization.

61661401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64090.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 61661401 is about 7852.4773797828. The cubic root of 61661401 is about 395.0673409730.

The spelling of 61661401 in words is "sixty-one million, six hundred sixty-one thousand, four hundred one".